I'm back with my 96 D21 King Cap problem truck. The speedo works and the offending sensors have been dealt with. Now, I've gotten everything except the EGR sensor to reset itself and it's driving me insane. The smog tester remembers bits and pieces about driving long distances in third gear at 40 mph; taking hard runs up the freeway and coasting downhill in lower gears, then putting four gallons of gas in so there is about half to three quarters of a tank before checking codes. Don't laugh, that's what got the cat to reset itself off the code list. Now, it's the EGR isn't resetting. Not that it isn't working, the code won't reset off the bloody computer. Might anyone please have, or know where I can find the Nissan service bulletin about how to get this danged thing to clear all the codes from the computer so I can smog check it? Thank you!

Thanks, hrd bdy, yes, it's been cleared by scanner. The computer has to run through its diagnostics to test each sensor and have them reset to clear them from the log. After all repairs, the EGR and cat hadn't reset. The cat reset after the 40 mph and four gallons of gas, but the EGR isn't resetting after the self tests. Not that it isn't working, it just won't tell the computer it's reset so the code dumps from the log and all codes are gone. The service bulletin stating what driving methods are necessary to get them to reset is old according to the smog guy and he no longer has it. He says Nissans are notoriously difficult to get to reset. He suggested contacting a Nissan dealer for information but no one knew what I was talking about, so I'm here and searching on line for info.

Officially, it's called the "Drive Cycle" to trigger the computer to diagnose and reset itself. I'd successfully gotten it to test and reset every code except the EGR, so I focused on that portion of the Drive Cycle. Nissans have the deserved reputation of being some of the worst for this issue. I can definitely see why! After making sure I followed the instructions as precisely as humanly possible (find anywhere in a large city such as Los Angeles where anyone can drive for three minutes, uninterrupted, in third gear at 40 mph!), repeating it three times in hopes it would be cumulative and not exact, I took the truck in for the seventh time for the codes to be read prior to testing. In California, older vehicles fall into the 'Star" smog section where they must be taken to Star facilities where the codes are read prior to testing. It required SEVEN readings and multiple drive cycles but every code FINALLY reset and erased from the computer. One sensor was cleaned; one sensor replaced; speedometer removed from the dash and all screws tightened; then several days and three tanks of gas spent so the bloody vehicle would pass California smog testing. 18 years old, nearly 197,000 original miles on the original engine and a steady 20+ mpg combined city/freeway driving. I'm not sure at this point I would go through all of this again to re smog it in two years, but thanks to your help here, it is FINISHED! Thank you!

OK, it appears to be the specific Nissan Drive Cycle Routine I'm seeking. I wonder if the one for 1997 would be the same?

Im having the same issue with my 1997 hardbody.. I've taking to the smog guy 3 different times and he's told me the same thing, drive around 40 mph and the slow down, drive it in town he say's. It's been driving me nuts! I don't have any check engine codes to clear, I've hooked it up to my scanner and no codes. I took it to a buddy and he checked the egr valve for me and says it works, he thinks I may have an evap leak some where.